Abstract: To reduce the characteristic size of cut tobacco, promote the uniformity of cut tobacco structure, and avoid cut tobacco tangling during processing, a flexible controlling device for the cut tobacco structure of slim cigarettes was designed, which consisted of a flexible tobacco screening unit and a tobacco cutting unit. Dried cut tobacco is transported into the flexible screening device by a vibrating trough, under the cooperation of the moving roller and the flake nails, the agglomerated tobacco is loosened, medium and short strands drop into the downstream vibrating trough through the openings, and long strands are conveyed to the cutting unit and cut into the shorter strands of the setting length by a set of rotating knives and a set of fixed knives. The device was tested with the cut tobacco for cigarette brand "Nanjing", and the results showed that:after the flexible controlling, 1) the proportion of long strands in flavored cut tobacco decreased by 10.29 percentage points, those of medium strands and short strands increased by 5.17 and 4.96 percentage points respectively, the characteristic size decreased by 17.96%, and the uniformity coefficient reduced slightly; 2) the proportion of long strands in break-out rods lowered by 15.89 percentage points, those of medium strands and short strands increased by 10.87 and 4.17 percentage points respectively, the characteristic size decreased slightly, and the uniformity coefficient increased by 7.14%, comparing with traditional processing means. It suggested that this technology was beneficial to improving the structural distribution of cut tobacco for slim cigarettes.